Re: Limiting load of certain processes

From: Jan Engelhardt
Date: Thu Jun 21 2007 - 14:26:24 EST



On Jun 21 2007 19:50, Jan Kandziora wrote:
>
>Dear all,
>
>I like to use an old DOS/Clipper application through DOSEMU on a Linux
>application server in a hotel. It works, but (as usual with DOS), it causes
>a processor load of 100% in certain situations, while just waiting for user
>interaction.

That's how it is. When DOS was written, cpu relaxing like the HLT instruction
was not known yet (or was it?), so everything was (and still is) a busy loop.

(Yes, including today's typical x86 BIOSes. Aw crap!)

Of course there may be hacks that try to figure out if a DOS window is idle,
waiting for user input. (Seems like a new invention in Windows 2000 and up).
Since dosemu and all the emulators are not running a genuine Microsoft DOS /
have source, it should be easy game for them to wait non-busily. Or maybe
busy-waiting is _part_ of the emulation; maybe some DOS driver(s) require it.


Jan
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